JP3344086B2 - Ion implanter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion implanter for starting a beam in a fully automatic manner according to set implantation conditions.

[0002]

2. Description of the Related Art In an ion implantation apparatus, an impurity to be diffused is ionized by an ion source, ions are extracted from the ion source by a strong electric field to form a beam, and then only desired ions are subjected to mass spectrometry using a magnetic field. Selective extraction, then ion beam acceleration, shaping,
Impurities are implanted into the ion irradiation target by irradiating the ion irradiation target by performing deflection, scanning, etc., and the impurities that determine device characteristics in the semiconductor process are controlled to an arbitrary amount and depth. The ability to implant well has made it an important device in current integrated circuit manufacturing.

In the above-described ion implantation apparatus, a controller controls the operation of each part of the apparatus by fully inputting the implantation conditions such as the mass number (mass value) of the ions, the beam current, and the beam energy. There is something to do.

The controller of the ion implantation apparatus has a data table in which several implantation conditions and optimum values of various parameters corresponding to the implantation conditions are registered in advance for each mass value. The beam start-up process is performed as follows.

First, the controller approximately obtains initial values of various parameters for the set injection conditions from the data table.

Next, the controller controls the ion source based on the initial values of the various parameters obtained above, converts the ion species into plasma, enables extraction of the ion beam, and then turns on the extraction power supply. A high voltage is applied between the ion source and the extraction electrode to extract ions from the ion source and form a beam.

Next, the controller controls the acceleration power supply so that the acceleration voltage becomes the initial value, and sets the beam energy. Further, the controller adjusts an analysis magnet current supplied to the mass spectrometer and performs a mass search for selectively extracting only desired ions.

After the above mass search is completed, the controller
Beam current adjustment is performed in the sequence shown in the flowchart of FIG. First, it is determined whether the ion species is a gas ion species such as BF ₃ or a solid ion species such as metal arsenic which needs to be evaporated using a vaporizer (S5).
1) If the gas ion species, control the flow rate of the gas supplied to the ion source (S52). Next, a beam setup process for adjusting various parameters related to the ion source is performed (S53). In the case of a Freeman-type ion source, this beam setup processing means “arc current”, “filament current”, “source magnet current”, “gas flow rate”
And adjusting the parameters such as ECR
(Electron Cyclotron Resonance) In the case of a microwave ion source such as an ion source, the "source magnet current"
This is to adjust parameters such as "microwave power" and "gas flow rate". The controller adjusts the above-mentioned various parameters so that the measured value of the beam current approaches the set value while monitoring the beam current (the so-called target current) measured by the beam current measuring unit provided in the injection chamber. .

If the beam current falls within a range of ± 10% of the set value (predetermined range) by the above-described beam setup processing (S54), extraction electrode control for adjusting the position of the extraction electrode is performed (S55). ). As shown in FIG. 11, the extraction electrode 51 is connected to a plasma chamber 52 of an ion source.
And is linearly moved in the direction of arrow A and arrow B by being driven by an electrode driving mechanism (not shown), and is turned in the direction of arrow C. If the beam passage hole 51a of the extraction electrode 51 and the beam extraction hole 52a of the plasma chamber 52 are displaced in the direction A, a large amount of the ion beam extracted from the beam extraction hole 52a hits the electrode surface of the extraction electrode 51. The beam passing through the passage hole 51a is reduced. If such a displacement of the extraction electrode 51 occurs, it is difficult to obtain a target beam current even if other parameters are adjusted. For this reason, conventionally, the extraction electrode control is always performed when the beam current enters a range of ± 10% with respect to the set value.

When the position of the extraction electrode changes due to the above-described extraction electrode control, the incident angle of the ion beam entering the mass analysis unit located downstream thereof also changes, so that the magnetic field intensity (magnetic flux density) in the analysis tube of the mass analysis unit is changed. Need to be fine-tuned. Therefore, after the extraction electrode control, mass tracking control for finely adjusting the analysis magnet current is performed (S56 in FIG. 10).

Thereafter, the beam current is set to ± 3 with respect to the set value.
The above-described beam setup process is executed until the beam current falls within the range (predetermined range) (S58). If the beam current falls within the appropriate range (YES in S57),
The process proceeds to the beam monitoring operation (S59). This beam monitoring operation is to monitor the beam current for a predetermined time to confirm the stability of the beam.

With the above processing, the apparatus start-up mode is completed, and the process shifts to the next injection processing mode.

[0013]

The above-described extraction electrode control and mass follow-up control are quite time-consuming controls in the full-automatic beam start-up operation. Since these controls take a long time, the beam current adjustment must be performed. The execution time will be longer,
Beam start-up time is longer.

In the conventional ion implantation apparatus, since there is no criterion for judging the necessity of executing the extraction electrode control and the mass tracking control, the extraction electrode control and the mass tracking control are always performed when adjusting the beam current. . That is, conventionally, even in a state where it is not necessary to execute the extraction electrode control and the mass following control,
Unnecessary control is performed because the state cannot be recognized, and there is a problem that it takes a long time to adjust the beam current at the time of starting the beam every time.

The present invention has been made in view of the above, and an object of the present invention is to provide an ion implantation apparatus capable of shortening a beam current adjustment time.

[0016]

According to the present invention, there is provided an ion implantation apparatus which is disposed opposite to a beam extraction hole formed in an ion source for generating ions, and includes an extraction electrode for extracting ions from the beam extraction hole. Extracting electrode driving means for changing the position of the extracting electrode with respect to the ion source, and selecting only ions of a specific mass by a mass spectrometry using a magnetic field from an ion beam passing through a beam passage hole formed in the extracting electrode. Mass extraction means, and the current of the ion beam reaching the target through the mass analysis means,
Beam current adjusting means for controlling various parameters so as to be set values and performing beam current adjustment, and in order to solve the above-mentioned problems, the following means are taken. It is a feature.

That is, the ion implantation apparatus includes a beam center-of-gravity position detecting means for detecting a center of gravity of the ion beam reaching the target, and a loss current generated when the ion beam extracted from the ion source strikes the electrode surface of the extraction electrode. And a loss current detecting means for detecting the loss current. Then, the beam current adjusting means includes a center-of-gravity position shift determining means for determining whether the center of gravity of the ion beam is within a predetermined proper range, and the loss current is within a predetermined proper range. And determining whether there is a shift in the position of the extraction electrode with respect to the ion source when the extraction electrode is out of the proper range, and determining the center-of-gravity position deviation determination means and the extraction electrode deviation determination means. Based on the result, it is necessary to execute extraction electrode control processing for controlling the extraction electrode driving means to adjust the position of the extraction electrode with respect to the ion source and mass analysis means control processing for adjusting the magnetic field strength of the mass analysis means. Control execution necessity judging means for judging.

[0018]

According to the above arrangement, the position of the center of gravity of the ion beam reaching the target is detected, and it is determined whether or not the position of the center of gravity is within a predetermined appropriate range. further,
The loss current generated by the ion beam extracted from the ion source on the electrode surface of the extraction electrode is detected, and it is determined whether or not the loss current is within a predetermined appropriate range. These are used as criteria for judging the necessity of executing the extraction electrode control process and the mass spectrometer control process.

When the extraction electrode is displaced from the proper position,
Because the beam is not extracted straight from the ion source,
The trajectory of the ion beam shifts, and the center of gravity of the beam on the target shifts. If the magnetic field intensity of the mass spectrometer is not appropriate, a deviation occurs in the deflection angle of the desired ion, and the center of gravity of the beam on the target also shifts. Therefore, if there is a displacement of the center of gravity of the beam,
It is necessary to execute at least one of the extraction electrode control processing and the mass analysis means control processing.

Incidentally, the extraction electrode is shifted from the proper position,
Even if the magnetic field intensity of the mass spectrometer also deviates from an appropriate value, no deviation occurs in the position of the center of gravity of the beam if the conditions are such that the deviations are corrected. Therefore, even if there is no deviation in the position of the center of gravity of the beam, the extraction electrode control processing and the mass analysis means control processing are not necessarily unnecessary.

When the extraction electrode is displaced from the proper position, the ion beam extracted from the ion source hits the electrode surface without passing through the beam passage hole of the extraction electrode, and a loss current flows through the extraction electrode. Accordingly, it is possible to determine the presence or absence of a shift of the extraction electrode from the magnitude of the loss current, and it is not necessary to perform the extraction electrode control process when the loss current is within an appropriate range.

Therefore, when neither the displacement of the center of gravity of the beam nor the displacement of the extraction electrode occurs, it is not necessary to execute both the extraction electrode control processing and the mass analysis means control processing. If there is no displacement of the center of gravity of the beam but there is a displacement of the extraction electrode, it is necessary to execute both of the above control processes. If there is a displacement of the center of gravity of the beam but no displacement of the extraction electrode, there is no need to execute the extraction electrode control processing. The beam current adjusting means of the present invention is provided with means for performing the above-mentioned various determinations (gravity center position deviation determining means, extraction electrode deviation determining means, control execution necessity determining means).

Thus, when the extraction electrode control processing and / or the mass analysis means control processing is unnecessary,
Since beam current adjustment can be performed without unnecessary control processing, the beam current adjustment time can be shortened.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 2, the ion implantation apparatus according to the present embodiment has an ion source 1 for ionizing ion species and an extraction electrode unit 2 for extracting ions from the ion source 1.
A mass spectrometer 3 (mass spectrometer) for selectively extracting only desired ions by mass spectrometry using a magnetic field; and an injection chamber 4 for setting a wafer and performing an injection process.

A gas box 5 for supplying gaseous ion species such as BF ₃ into the plasma chamber is connected to the ion source 1. The ion source 1 is also connected to a vaporizer (not shown) for evaporating solid ion species and introducing the same into the plasma chamber. As the ion source 1, for example, a known source such as a Freeman type ion source or an ECR ion source can be used.

Further, the ion implantation apparatus is provided with the ion source 1 described above.
(An ion source power supply 6 for supplying power to each part (source magnet or filament for a Freeman type ion source, source magnet or magnetron for an ECR ion source), and an analysis magnet of the mass spectrometer 3 And an analysis magnet power supply 9 for supplying power to the power supply.

As shown in FIG. 3, the extraction electrode section 2
It comprises an extraction electrode 21, a ground electrode 22, and an electrode drive mechanism (not shown). The plasma chamber 11 of the ion source 1 has a slit-shaped beam extraction hole 11a for emitting ions from plasma generated in the chamber.
Are formed, and the extraction electrode 21 is disposed at a position facing the beam extraction hole 11a. The ground electrode 22 is located downstream of the extraction electrode 21.
And it is arranged facing.

[0029] the ground electrode 22 is grounded reference potential, and lead electrodes 21, as a negative potential than the ground electrode 22, a negative voltage V _d is applied from the deceleration power supply 8. Then, in the above plasma chamber 11 so that the positive terminal of the extraction power supply 7 is connected, the extraction voltage V _e of the high voltage from the extraction power supply 7 is applied.
As a result, a potential difference (extraction voltage V _e + deceleration voltage V _d ) is generated between the plasma chamber 11 and the extraction electrode 21 to form a strong external electric field, and the plasma generated in the plasma chamber 11 by the external electric field is generated. The positive ions in the
The ion beam is extracted from the ion extraction hole 11a, and an ion beam is formed. As described above, the extraction electrode 2
By setting 1 to a potential lower than that of the ground electrode 22, it is possible to prevent backflow of electrons generated downstream of the extraction electrode unit 2 (a phenomenon in which electrons flow into the plasma chamber 11).

The extraction electrode 21 and the ground electrode 22 are
Driven by the electrode driving mechanism, the actuator linearly moves in the directions of arrows A and B and rotates in the direction of arrow C. By driving these electrodes 21 and 22 in the direction A (the direction that is horizontal and parallel to the electrode surface), the electrode displacement (the ion extraction hole 11a of the plasma chamber 11 and the electrode 21.
22 with respect to the beam passage holes 21a and 22a) can be adjusted. Further, by driving the electrodes 21 and 22 in the direction B (the direction that is horizontal and perpendicular to the electrode surface), the gap between the electrodes 21 and 22 and the plasma chamber 11 can be adjusted. By rotating the electrodes 21 and 22 in the C direction, the angle of the electrode surface with respect to the beam can be adjusted. The extraction electrode 21 and the ground electrode 22 are mounted on a common frame and integrated, and both electrodes 21 and 22 are integrally driven by an electrode driving mechanism.

As shown in FIG. 4, the injection chamber 4 is provided with a disk 13 which holds a plurality of wafers 12 and moves in the direction of arrow D while rotating in the direction of arrow E. During the injection process, the disk 13 enters the Faraday cup 14 as shown by a two-dot chain line to perform a mechanical scan operation. Downstream of the disk 13 is a beam catch plate 15 for beam profile monitoring.
Is provided. When the implantation process is not performed, the disk 13 is at the retreat position shown by the solid line and retreats outside the Faraday cup 14, so that the ion beam is applied to the beam catch plate 15.

As shown in FIG. 5, the beam irradiation surface of the beam catch plate 15 has j × k (j in the X direction).
, Beam catchers 16 in the Y direction) are attached in a floating state insulated from other members. The beam catchers 16 are arranged at regular intervals at positions corresponding to the coordinate points of the X and Y coordinates. Lead wires 16a individually extend from the beam catch portions 16 so that the electric charge of the ion beam hitting the beam catch portions 16 flows to the beam measuring portion 17 via the lead wires 16a. ing.

The beam measuring section 17 obtains the current density of the ion beam caught by each beam catching section 16. That is, the beam measuring unit 17 converts the current (instantaneous value) flowing through each of the beam catching units 16 to a voltage, then performs analog / digital conversion, and performs the following calculation. That is, assuming that the current flowing through each of the beam catch portions 16 is I and the area of the beam catch surface of the beam catch portions 16 is S, the current density is obtained by I / S. Then, the beam measuring section 17 sends the data of the beam current density in each of the beam catch sections 16 to the controller 18 (beam current adjusting means) shown in FIG.

The controller 18 recognizes a current density distribution (a so-called beam profile) of the ion beam based on the beam current density data sent from the beam measuring unit 17 and calculates the position of the center of gravity of the ion beam. That is, the X coordinate (referred to as X _cen ) of the position of the center of gravity is determined by the following equation (1), and the Y coordinate (referred to as Y _cen ) of the position of the center of gravity is determined by the following equation (2).

[0035]

(Equation 1)

[0036]

(Equation 2)

Here, X _n = 1, 2,... J, Y _n = 1,
2,... K. Further, I _xn is a value obtained by adding the beam current densities of all the beam catchers 16 in the row of X _n . For example, I _x1 is (1, 1), (1, 2),.
It is a value obtained by adding the beam current densities of the beam catchers 16 at the (1, k) coordinate point. Similarly, I _yn is Y
It is a value obtained by adding the beam current densities of all the beam catch units 16 in the column of _n .

The controller 18 determines whether or not the position of the center of gravity (X _cen , Y _{ce n} ) obtained by the above calculation is within a predetermined appropriate range. It is used as a criterion for judging the necessity of.

As shown in FIG. 6, when the extraction electrode 21 and the ground electrode 22 of the extraction electrode section 2 are displaced from the proper positions (the center of the ion extraction hole 11a of the plasma chamber 11 and the beam passage holes of the electrodes 21 and 22). 21a, 22a), the trajectory of the ion beam (shown by a solid line) deviates from an appropriate beam trajectory (shown by a two-dot chain line), and the center of gravity of the beam applied to the beam catch plate 15 Shift occurs.

As shown in FIG. 7, even if the extraction electrode 21 and the ground electrode 22 are at appropriate positions, the mass spectrometer 3
If the magnetic field strength (magnetic flux density) in the analysis tube of
A deviation occurs in the deflection angle of a desired ion, and the trajectory of the ion beam (shown by a solid line) deviates from an appropriate beam trajectory (shown by a two-dot chain line).
Shift occurs in the center of gravity of the beam radiated to the surface.

As described above, if there is a deviation of the center of gravity of the ion beam irradiated on the beam catch plate 15 beyond an allowable range, it is necessary to execute at least one of the extraction electrode control and the mass tracking control. You can see that.

As shown in FIG. 8, when the extraction electrode 21 and the ground electrode 22 are displaced from the proper positions and the magnetic field strength in the analysis tube of the mass spectrometer 3 is not proper, the two are mutually If the conditions are such that the deviations are corrected, no deviation occurs in the position of the center of gravity of the beam applied to the beam catch plate 15. Therefore, in this embodiment, the displacement of the center of gravity of the beam is detected, and the magnitude of the loss current flowing through the
1 and the presence / absence of displacement of the ground electrode 22 are detected.

That is, as shown in FIG. 3, when the extraction electrode 21 is displaced from the proper position, most of the ion beam extracted from the ion source 1 is supplied to the beam passage hole 2 of the extraction electrode 21.
Upon the electrode surface without passing through the 1a, it will flow to the ground portion as a loss current I _L. As deviation of the lead electrode 21, the greater the loss current I _L flowing through the extraction electrode 21.
Thus, the magnitude of the loss current I _L flowing through the extraction electrode 21, it is possible to determine the presence or absence of misalignment of the lead electrode 21.

In this embodiment, a loss current detecting means such as a current detecting resistor is provided inside the deceleration power supply 8 provided between the extraction electrode 21 and the grounding portion. Ross current detected by the current loss detecting means I _L, the controller 1
8 (see FIG. 2). The controller 18 includes:
It is determined whether or not the above-mentioned loss current _IL is within a predetermined appropriate range, and this is used as a criterion for determining the necessity of the extraction electrode control.

[0045] As described above, the controller 18, the two criteria of a loss current I _L flowing through the centroid position and the extraction electrode 21 of the beam, to determine the necessity of the extraction electrode control and mass following control. From the above two criteria, the following determinations can be basically made. If the center of gravity position and Ross current I _L of the beam both within the acceptable range, it is not necessary to perform the extraction electrode control and mass follow-up control. Although the center of gravity of the beam is within the allowable range, if the loss current I _L is out of the allowable range, it is necessary to perform the extraction electrode control and mass follow-up control. When the center of gravity of the beam is out of the allowable range but the loss current _IL is in the allowable range, it is not necessary to execute the extraction electrode control, but the mass following control is necessary. Further, if neither the center of gravity position and Ross current I _L of the beam is out of the allowable range,
It is necessary to perform at least the extraction electrode control, and it is necessary to execute the mass tracking control along with the execution of the extraction electrode control.

The controller 18 controls the gas box 5, ion source power source 6, extraction power source 7, deceleration power source 8, analysis magnet power source 9, and other parts of the ion implantation apparatus such as an electrode driving mechanism (not shown) shown in FIG. Various parameters are adjusted while controlling, and the beam is automatically started.

The controller 18 has a CPU (Centra
l Processing Unit), a memory, and a microcomputer including an input / output unit and the like. FIG. 9 is a functional block diagram showing a functional module configuration for the beam current adjustment processing of the controller 18. As shown in the figure, the controller 18 calculates a beam center-of-gravity position calculating unit 18 that calculates a beam center-of-gravity position according to the above equations (1) and (2).
and a, center of gravity position shift judgment section 18b to determine whether in a proper range beam centroid position is predetermined (gravity position deviation determining means), within proper range loss current I _L reaches a predetermined An extraction electrode displacement determining unit 18c (extraction electrode displacement determining means) that determines whether or not there is a displacement of the extraction electrode 21, and a determination result of the center-of-gravity position displacement determining unit 18b and the extraction electrode displacement determining unit 18c. Control execution necessity determining unit 18 that determines whether or not to execute the extraction electrode control processing and the mass tracking control processing (mass analysis means control processing) based on
d (control execution necessity determination means), an extraction electrode control unit 18e for performing extraction electrode control processing, a mass following control unit 18f for performing mass following control processing, and parameters other than the above-mentioned extraction electrode control and mass following control parameters And a beam setup processing unit 18g for performing a beam setup process for adjusting the distance. The parameters adjusted in the beam setup process are as follows in the case of the Freeman type ion source.
Parameters such as "arc current", "filament current", "source magnet current", and "gas flow rate". In the case of a microwave ion source, "source magnet current", "microwave power", "gas flow rate" And the like.

In the above configuration, the automatic beam start-up operation by the controller 18 will be described below.

First, an operator operates an input operation unit (not shown) to set injection conditions (mass value, beam current, beam energy). Then, the set injection condition is taken into the controller 18. In a storage device (not shown) of the controller 18, optimal value data of various parameters for injection conditions of some patterns are registered. These registration data are data collected by the operator manually starting up the ion implantation apparatus in an optimum state in advance. Controller 1
Reference numeral 8 is such that initial values of various parameters with respect to set injection conditions are approximately obtained based on parameters registered in advance.

That is, the controller 18 selects two upper and lower injection conditions closest to the set value of the beam current from among several registered injection conditions, and obtains the registered data of the parameters of these two injection conditions from the registered data. An initial value of a parameter relating to the beam current is approximately determined by linear primary interpolation correction. Similarly, an initial value of a parameter related to the beam energy is also obtained.

Here, the parameters relating to the beam current are parameters that largely depend on the control of the beam current, and mainly include the parameters of the ion source (in the case of the Freeman type ion source, “arc current” and “filament current”). , “Source magnet current”, “gas flow rate”, etc. In the case of a microwave ion source such as an ECR ion source,
"Source magnet current", "Microwave power",
"Gas flow" etc.). The parameters related to the beam energy refer to parameters such as “extraction voltage” and “deceleration voltage” that largely depend on controlling the beam energy.

Thereafter, the controller 18 controls each part of the ion source 1 based on the initial values of the various parameters obtained above to convert the ion species into plasma in the plasma chamber 11 and to extract the ion beam.
Next, the extraction power source 7 and the deceleration power source 8 are turned on, a high voltage is applied between the plasma chamber 11 of the ion source 1 and the ion source and the extraction electrode, and ions are extracted from the ion source 1 to form an ion beam. .

Next, the controller 18 controls the analysis magnet power supply 9 to adjust the analysis magnet current supplied to the mass spectrometer 3, and performs a mass search for selectively extracting only desired ions.

After completion of the mass search, the controller 18
Performs beam current adjustment in the sequence shown in the flowchart of FIG. First, the center of gravity (X _cen , Y _cen ) of the ion beam is calculated based on the beam current density data sent from the beam measuring unit 17, and the center of gravity (X _cen ) is calculated.
_cen , Y _cen ) are determined to be within a predetermined appropriate range (S1). For example, when 17 × 17 (17 in the X direction and 17 in the Y direction) beam catch portions 16 are attached to the beam catch plate 15 shown in FIG. 5, 8 ≦ X _cen ≦ 10 8 ≦ Y _cen ≦ In the case of 10, it is determined that there is no displacement of the center of gravity. Note that the above-mentioned appropriate range, which serves as a criterion for determining the presence or absence of the displacement of the center of gravity, can be arbitrarily set.

If it is determined in S1 that there is a displacement of the center of gravity, it is determined whether the displacement of the center of gravity is a displacement in the horizontal direction (X direction) (S2). Then, in S2, Y
For ES, the loss current I _L from the current loss detecting means in the deceleration power supply 8, it is determined whether it is within the proper range determined in advance (S3). And, for example, I _L <1.5 mA
When there is no horizontal displacement of the extraction electrode 21, I _L ≧ 1.5
When it is mA, it is determined that there is a deviation in the horizontal direction. The above-mentioned appropriate range, which is used as a criterion for determining the presence or absence of an electrode shift, is experimentally obtained and can be set arbitrarily. Naturally, the appropriate range varies depending on the amount of current of the beam extracted from the ion source 1.
When the implantation conditions are set, the appropriate range is automatically changed according to the set value of the beam current.

If it is determined in step S3 that there is a horizontal displacement of the extraction electrode 21, the position of the extraction electrode 21 in the horizontal direction (direction A in FIG. 3) is controlled via an electrode driving mechanism (S4). The extraction electrode horizontal control means that the extraction electrode 21 is gradually moved in the horizontal direction with a constant movement width, and the loss current I
_This is to detect the position of the extraction electrode 21 where _L is minimum.

If NO in S2, YES in S3
In the case of or after execution of S4, it is determined whether the displacement of the center of gravity is a displacement in the vertical direction (Y direction) (S5). Then, in the case of YES in S5, the position of the angle of the electrode surface with respect to the beam of the extraction electrode 21 is controlled via the electrode driving mechanism (S6). That is, if the angle of the electrode surface with respect to the beam of the extraction electrode 21 is not a right angle, the trajectory of the beam will be shifted in the vertical direction, so that it is necessary to control the extraction electrode angle. The extraction electrode angle control means that the extraction electrode 21 is rotated in the direction C in FIG.
The control is performed such that the position of the center of gravity in the (direction) falls within an appropriate range.

In the case of NO in S5 or after the execution of S6, the mass follower for controlling the analysis magnet power supply 9 to finely adjust the analysis magnet current (finely adjust the magnetic field intensity in the analysis tube of the mass analysis unit 3). Control is performed (S7).

[0059] Also, when it is determined that there is no center-of-gravity position shift in the S1, within the appropriate range for loss current I _L reaches a predetermined (eg, I _L <1.5 mA) to determine whether the (S8) . Here, if the loss current _IL is out of the proper range, horizontal control of the extraction electrode is performed (S9), and then S
Then, the flow goes to 7 to perform mass tracking control. On the other hand, if the loss current I _L in the proper range in S8, it is determined that there is no need to perform the extraction electrode control and mass follow-up control proceeds to the next process.

In the case of YES in S8 or in S7
After the execution, the beam setup process is performed so that the beam current falls within a range of ± 3% (predetermined range) with respect to the set value (S11). That is, the controller 18
Adjusts various parameters such that the target current approaches the set value while monitoring the beam current (target current) at the injection position.

If the beam current falls within the appropriate range by the beam setup process (YE in S10)
S), the process proceeds to the beam monitoring operation (S12). This beam monitoring operation is to monitor the beam current for a predetermined time to confirm the stability of the beam. For example,
The beam current may become unstable due to frequent discharges in the ion source 1 or the like. If the controller 18 detects such a state during the beam monitoring period, the controller 18 may activate a beam abnormality display, activate an alarm buzzer, or the like. An alarm operation is performed to notify the operator of the beam abnormality. If the stability of the beam is confirmed by the beam monitoring operation, the beam start-up mode is terminated, and the mode is shifted to the injection processing mode.

As described above, the ion implantation apparatus according to the present embodiment is provided so as to face the beam extraction hole 11a formed in the ion source 1 and to have the extraction electrode 21 for extracting ions from the beam extraction hole 11a. Extraction electrode driving means for changing the position of the extraction electrode 21 with respect to the ion source 1, and a specific mass of the ion beam passing through the beam passage hole 21 a formed in the extraction electrode 21 by a mass spectrometry using a magnetic field. A mass spectrometer 3 for selectively extracting only ions,
Beam centroid position detecting means (beam catch plate 1) for detecting the centroid position of the ion beam reaching the target
5. Beam measuring unit 17, beam center-of-gravity position calculating unit 18a)
When various as the loss current detecting means for detecting the loss current I _L ion beam extracted from the ion source 1 generates when the electrode surface of the lead electrode 21, the current of the ion beam reaching the target reaches the set value A controller 18 that controls a parameter to adjust a beam current, wherein the controller 18 determines whether or not the center of gravity of the ion beam is within a predetermined appropriate range. It is determined whether or not the loss current _IL is within a predetermined appropriate range. If the loss current _IL is out of the appropriate range, it is determined that the position of the extraction electrode 21 with respect to the ion source 1 is shifted. Part 18
c, and a control execution necessity judging part 18d for judging the necessity of executing the extraction electrode control processing and the mass following control processing based on the judgment results of the two judgment parts 18b and 18c. is there.

Thus, when the extraction electrode control processing and / or the mass tracking control processing is unnecessary, the unnecessary control processing is omitted and the beam current adjustment is performed, so that the beam current adjustment time can be shortened. Thus, the beam can be set up in a short time.

Further, the ion implantation apparatus of this embodiment first determines the necessity of the extraction electrode control processing and the mass tracking control processing, and executes the control processing if necessary to execute the extraction electrode shift and mass shift. Eliminate the inadequacy of the analysis unit 3, and then
Since the beam setup process is performed,
Accurate beam setup processing can be performed in a stable state. For example, when the extraction electrode 21 is displaced, a large amount of the ion beam hits the electrode surface of the extraction electrode 21 and a large amount of secondary electrons are emitted from the electrode surface. For this reason,
Discharge is likely to occur due to dielectric breakdown between the extraction electrode 21 and the ion source 1, and accurate beam setup processing cannot be performed. In the present embodiment, as described above, since the extraction electrode displacement has been eliminated prior to the beam setup process,
Accurate beam setup processing is possible.

In this embodiment, the beam catch plate 15, the beam measuring unit 17, and the beam center position calculating unit 18a of the controller 18 constitute the beam center position detecting means. The position of the center of gravity of the beam is calculated, and the calculation result is sent to
You may send to. In the above embodiment,
It is intended to clarify the technical contents of the present invention, and should not be construed as being limited to such specific examples in a narrow sense. Various modifications may be made within the spirit of the present invention and the scope of the claims. Can be implemented.

[0066]

As described above, the ion implantation apparatus according to the present invention has a beam center of gravity detecting means for detecting the center of gravity of an ion beam reaching a target, and an ion beam extracted from an ion source. A loss current detecting means for detecting a loss current generated on the surface, and a beam current adjusting means for performing a beam current adjustment, wherein the beam current adjusting means sets a center of gravity of the ion beam within a predetermined appropriate range. A center-of-gravity displacement determining means for determining whether or not the extraction current is present, and determining whether or not the loss current is within a predetermined appropriate range. The extraction electrode shift determining means for determining that there is an output electrode driving means based on the determination results of the center of gravity position shift determination means and the extraction electrode shift determination means. Control execution necessity determining means for determining whether execution of the extraction electrode control processing for controlling the position of the extraction electrode with respect to the ion source and the mass analysis means for adjusting the magnetic field intensity of the mass analysis means is required. Configuration.

Therefore, when the extraction electrode control processing and / or the mass analysis means control processing is unnecessary, it is possible to accurately judge the unnecessary processing. Therefore, the unnecessary control processing is omitted and the beam current adjustment is omitted. Can be performed, and the beam current adjustment time can be shortened.

[Brief description of the drawings]

FIG. 1, showing an embodiment of the present invention, is a flowchart illustrating a beam current adjusting operation by a controller of an ion implantation apparatus.

FIG. 2 is a block diagram illustrating a schematic configuration of the ion implantation apparatus.

FIG. 3 is a fragmentary cross-sectional view for explaining beam extraction in the ion implantation apparatus.

FIG. 4 is an explanatory diagram for explaining a configuration near an implantation position of the ion implantation apparatus.

FIG. 5 is an explanatory diagram for explaining a configuration of a beam catch plate of the ion implantation apparatus.

FIG. 6 is an explanatory diagram for explaining the trajectory of the ion beam when the extraction electrode shifts in the ion implantation apparatus.

FIG. 7 is an explanatory diagram for explaining the trajectory of the ion beam when the magnetic field intensity of the mass analysis unit is inappropriate in the ion implantation apparatus.

FIG. 8 is a diagram showing an ion implantation apparatus in which the displacement of the extraction electrode occurs and the displacement of the center of gravity of the beam does not occur despite the improper magnetic field strength of the mass spectrometer. It is an explanatory view for explaining a track.

FIG. 9 is a functional block diagram showing a functional module configuration of a controller of the ion implantation apparatus.

FIG. 10 is a flowchart showing a beam current adjustment operation by a controller of a conventional ion implantation apparatus.

FIG. 11 is a cross-sectional view of main parts for describing extraction of a beam in the ion implantation apparatus.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 ion source 2 extraction electrode unit 3 mass analysis unit (mass analysis unit) 7 extraction power supply 8 deceleration power supply 15 beam catch plate (beam centroid position detection unit) 17 beam measurement unit (beam centroid position detection unit) 18 controller (beam current adjustment) Means 18a Beam center-of-gravity position calculating unit (beam center-of-gravity position detecting unit) 18b Center-of-gravity position shift determining unit (center-of-gravity position shift determining unit) 18c Leader electrode shift determining unit (leader electrode shift determining unit) 18d Control execution necessity determining unit (control) Execution necessity determination means) 21 extraction electrode

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01J 37/317 H01J 37/04 H01J 37/05 H01L 21/265 C23C 14/48

Claims (1)

(57) [Claims] 1. An extraction electrode arranged to face a beam extraction hole formed in an ion source for generating ions, and an extraction electrode for extracting ions from the beam extraction hole, and an extraction electrode for changing a position of the extraction electrode with respect to the ion source. Electrode driving means, mass analysis means for selectively extracting only ions of a specific mass from the ion beam passing through the beam passage hole formed in the extraction electrode by mass spectrometry using a magnetic field, and the mass analysis means A beam current adjusting means for controlling various parameters so that the current of the ion beam reaching the target after passing through the ion beam reaches a set value. A beam center-of-gravity position detecting means for detecting the position of the center of gravity of the ion beam, and an ion beam extracted from the ion source is applied to the electrode surface of the extraction electrode. A loss current detecting means for detecting a loss current generated beforehand, wherein the beam current adjusting means determines whether or not the center of gravity of the ion beam is within a predetermined appropriate range. And extracting electrode displacement determining means for determining whether or not the loss current is within a predetermined appropriate range, and determining that there is a shift in the position of the extracting electrode with respect to the ion source when the loss current is out of the appropriate range, Extraction electrode control processing for controlling the extraction electrode driving means to adjust the position of the extraction electrode with respect to the ion source based on the judgment results of the center-of-gravity position deviation judgment means and the extraction electrode deviation judgment means, and the magnetic field strength of the mass analysis means Control execution necessity judging means for judging the necessity of execution with the mass spectrometry means control processing for adjusting the control.